Processing semantically enriched content for interactive 3D visualizations

Interactive 3D graphics has become an essential tool in many fields of application: In manufacturing companies, e.g., new products are planned and tested digitally. The effect of new designs and testing of ergonomic aspects can be done with pure virtual models. Furthermore, the training of procedures on complex machines is shifted to the virtual world. In that way support costs for the usage of the real machine are reduced, and effective forms of training evaluation are possible. Virtual reality helps to preserve and study cultural heritage: Artifacts can be digitalized and preserved in a digital library making them accessible for a larger group of people. Various forms of analysis can be performed on the digital objects which are hardly possible to perform on the real objects or would destroy them. Using virtual reality environments like large projection walls helps to show virtual scenes in a realistic way. The level of immersion can be further increased by using stereoscopic displays and by adjusting the images to the head position of the observer. One challenge with virtual reality is the inconsistency in data. Moving 3D content from a useful state, e.g., from a repository of artifacts or from within a planning work flow to an interactive presentation is often realized with degenerative steps of preparation. The productiveness of Powerwalls and CAVEsTM is called into question, because the creation of interactive virtual worlds is a one way road in many cases: Data has to be reduced in order to be manageable by the interactive renderer and to be displayed in real time on various target platforms. The impact of virtual reality can be improved by bringing back results from the virtual environment to a useful state or even better: never leave that state. With the help of semantic data throughout the whole process, it is possible to speed up the preparation steps and to keep important information within the virtual 3D scene. The integrated support for semantic data enhances the virtual experience and opens new ways of presentation. At the same time the goal becomes feasible to bring back data from the presentation for example in a CAVETM to the working process. Especially in the field of cultural heritage it is essential to store semantic data with the 3D artifacts in a sustainable way. Within this thesis new ways of handling semantic data in interactive 3D visualizations are presented. The whole process of 3D data creation is demonstrated with regard to semantic sustainability. The basic terms, definitions and available standards for semantic markups are described. Additionally, a method is given to generate semantics of higher order automatically. An important aspect is the linking of semantic information with 3D data. The thesis gives two suggestions on how to store and publish the valuable combination of 3D content and semantic markup in a sustainable way. Different environments for virtual reality are compared and their special needs are pointed out. Primarily the DAVE in Graz is presented in detail, and novel ways of user interactions in such immersive environments are proposed. Finally applications in the field of cultural heritage, security and mobility are presented. The presented symbiosis of 3D content and semantic information is an important contribution for improving the usage of virtual environments in various fields of applications